EFFECTS OF SEVERAL SALURETIC-DIURETIC AGENTS ON RENAL HEMODYNAMICS

¹ Department of Pharmacology, College of Medicine, The University of Iowa, Iowa City, Iowa

Furosemide and ethacrynic acid have been reported to be effective in certain clinical situations in which patients would not be expected to respond favorably to mercurials. Inasmuch as mercurials possess the ability to increase renal vascular resistance, it was of interest to determine whether the differences in activity between the mercurials and furosemide or ethacrynic acid could be attributed to different effects on the renal vasculature. The left kidney of anesthestized dogs was perfused at constant flow with femoral arterial blood. In this preparation, furosemide and ethacrynic acid produced a significant decrease in renal vascular resistance at the time of maximal saluresis. Hydrochlorothiazide produced a significant increase in resistance, as did chlormerodrin. Utilizing the electromagnetic flowmeter, furosemide was found to increase renal blood flow in animals with intact kidneys. It was concluded that the ability of furosemide and ethacrynic acid to produce diuresis in conditions unresponsive to the mercurials might be explained on a hemodynamic basis, since mercurials are renal vasoconstrictors while furosemide and ethacrynic acid by their vasodilator action increase renal blood flow.